Arc light



A. IHLN ARC LIGHT Aug. 30,1927.

Filed Dec. 24, 1923 Inventor:

Alols Ihln;

a .1242: His Anborne Patented Aug. 30, 1927.

VUNITED STATES PATIENT OFFICE.

ALOIB IKLN, OI IBERLm-CHARLOTTENBUBG, GERMANY, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ARC LIGHT.

Application filled December 24, 1828, Serial No. 682,371, and in GermanyMay 5, 1923.

My invention relates to arc-lights in general and is especially adaptedto the socalled tungsten arc type othght,

In tungsten arc-lamps with contact lglll- 5 tion the form of theelectrodes at the point where the arc is found changes due to thetransfer of matter in the are from the cathode to the anode with theresult that the necessary contact between the electrodes 3 when the lampis at.rest is not always established. According to the invention, asatisfactory contact can be maintained between the electrodes regardlessof the deformation of the anode resulting from the are for the 5 reasonthat when the lamp is ut out, contact between the electrodes ta es placeat some other point than at the point where the arc is formed. Accordingto my invention, it is also possibleto cause the arc to change 3 itsposition by suitablgl shaping the cathode or by turning one or" th ofthe electrodes when they become separated at the time of ignition.

The means for accomplishing the foregoing and other useful ends arehereinafter more fully set forth and claimed, reference being had to theaccompanying sheet of drawings. In the accompanying drawings, severalforms of the device of my invention 0 are shown. Fig. 1 shows inelevation one type of tungsten lamp of my invention; Fig. 2 is a topview of the electrodes shown on an enlarged scale; Figs. 3, 4 and 5 aretop views of electrodes differing in type from those shown in Fig. 2. 1

' The tun ten lamp shown in the drawings consists of a glass receptaclea of the well known glow light shape having a stem base of enclosin thelead-in wires 6 and 0.. The lamp is aso provided with a rod-shapedcathode 9 supported by holders e and f. The cathode isbestprovided witha-sleeve of thorium oxide 9'.

. Lamps of this general class are well known in the art and are usuallyfilled with such gases as ar on or a mixture of argon and n trogen. Thelamp may be operated under varying pressure but preferably underdiminished pressure even as low as mm.

The lamp is also provided with a spherical anode 7:. held in place bythe rod-i in which rod a stri of bi-metal k is inserted. As shown in i2, the cathode g and the sleeve g have each an elbow along the region Z.It is at this point that the anode h turned on,

rests against the cathode when the lamp is not burning. At the momentthe current is the current is short-circuited by way of the electrodes 9and h so that a heavier current is caused to flow than after the arc isestablished. The reason for this is that before the arc is started, theline yoltage is only opposed by the resistor used I in connection withthe lamp, which resistor isnot shown in the figure.

As soon as the strip of bi-1netal becomes heated by the current flowingthrough it, the s herical anode h is drawn from the cathode and moved inthe direction of. the arrow parallel to the rod-shaped cathode g and gfuntil it arrives at a position similar to that 'of the dotted lines inwhich position it remains as long as the lamp is burning. It will beunderstood that the arc begins to form or is formed from the moment thatthe anode h separates from thecathode' As indicated in Fig. 4, the arcis thus maintained at some other point than the point of contact.

Referringto Fig. 2, it will be understood that the point of contact isbetween the anode h and the cathode at the elbow region Z where theanode is shown in solid lines, whereas the point at which the arc ismaintained is between the anode and the cathode at the .oint where theanode h is shown in clotted ines. A similar explanation applies to theconstruction shown in Figs. 3 and 5. In other words, the point ofarc-over on the anode in a device similar to that shown in Fig. 2 may beat a point a great many degrees away from the oint of contact. In someinstances, it may e almost 180 degrees away from the point of contact.For this reason, the point of contact cannot be badly influenced by theare so that even after the lamp has burned for a long period, a goodcontact is still preserved between the electrodes when the current isshut off. It will be understood that the abutment formed by the bend lat the cathode may also he brought about in any other suitable, manner,for instance, by means of a thickening of a cross-pin.

Although the presence of oxides at the cathode facilitates themaintenance of the are, the current flow at the contact on the otherhand is better ensured when both contact points at the anode and at thecathode consist of better contact and smootherma- Inn terial such astungsten. The design shown in Fig. 3 complies with this re uirement andoffers at the same time the RC vantage of a similar construction. Inthis form of design a piece of tungsten m which can be hemispherical,for instance, is pushed over the thorium oxide containing sleeve. g ofthe cathode g and it is against this piece that the hemisphericaltungsten anode will rest when the lamp does not burn. \Vhen the currentis turned on and the anode becomes separated from the cathode, the arc1s formed between the thorium oxide contaming sleeve g and the anodesurface about the oint of contact. The tungsten body which is pushedover the sleeve may have any suitable shape and so may the anode.

In the type of construction shown 1n Fig. 4, the anode It lies on thestraight part of the sleeve g but, when the current is turned on, theanode moves in the direction of the arrow as indicated by the dottedline, the direction of travel bein along the line 11. sloping withrespect to t is cathode g. The bend in the cathode in Fig. 4 is shownalong the region 0. Therefore, as the anode travels, the arc travelswith it and settles at some point, such as the point p, for example,Thus, also in this case, the shape of the cathode insures that theanode, when the current is cut oil from the lamp shall enga the cathodeat some point other than t e point p.

In the construction shown in Fi 5, the anode h, when the current is shute moves slantwise toward the rod-shaped cathodes g and g. which isstraight, but then the anode h is made to rotate about its axis while itmoves lengthwise. This is brought about by a suitable shape of the stripof bi-metal with which the holding stem is provided. The reverseoperation takes place when the current is turned ofi; therefore, in thiscase also, the arc finally settles at a point on the anode surface otherthan the point at which the anode enga es lthe cathode and other thanthat at w 'ch the ignition starts or takes place.

Instead of rotating the anode during the process of ignition or durinthe process of establishment of the arc wit respect to the cathode, itis possible, if necessary, to rotate the cathode with respect to theanode in order that the permanent arc may be formed itself with otherspots of the electrode surface than the spot of contact. This can beaccomplished for example by having the bi-metal element is lyin in ahorizontal position, Fig. 1, instead of m a vertical position, as shownin said figure in which case the electrode it, instead of travelingiin astraight line, as indicated by the dot-te line, Fig. 4, will travel inan arc of a circle, thereb giving the electrode a rotatin motion witrespect to the electrode 9. e same result can be obtained by having onebi-metal element in a vertical plane as in Fig. 1, and one bi-metalelement in a horizontal plane, in which case the Iii-metal element inthe vertical plane will cause the electrode h to travel, for example, ina direction parallel to the electrode 9, whereas the iii-metal elementin the horizontal plane will cause the electrode 71. to travel in adirection across the direction represented by the electrode g, therebyproducing the rotating efl'ect mentioned.

It will be two dissimilar metals secured together, each having acoeflicient of expansion difl'erent from the other. Bi-metal elements ofthis type are of course well known in the art.

The invention can be utilized in tungsten lamps having electrodes of anyshage, for instance, spherical of hemispherical. n this case, care mustbe taken to.insure a rotating motion of either or both electrodes whenthey become separated and at the time ignition takes place.

It will be understood that although I have 1 illustrated specific formsof construction of my invention as required by the statutes, I do notwish to limit myself to the constructions shown inasmuch as variationswill readily suggest themselves to those skilled in the art as a resultofthe disclosure in this specification.

What I claim as new and desire to secure by Letter Patent of the UnitedStates, is:-

1. In an arc lamp, 9. pair of electrodes normally in contact with eachother, means for se arating one of the ot er whereby an arc is startedin the region of contact, said means also serving for continuing themovement of said electrode to draw the are. away from the region ofcontact on the other electrode toward another region of said otherelectrode and to maintain the arc in the new region, thus 3 preventingrapid deterioration of said point of contact.

2. In an arc lamp, 9. pair of electrodes normally in contact with eachother, means for separating one of said electrodes from '1 theot erwhereby an arc is started in the region of contact, said means. alsoserving for continuing the movement of said electrode to draw the areaway from the region of contact on the other electrode toward anotherregion of said other electrode and to maintain the arc in the newregion, thus preventing rapid deterioration of said point of contact,said means serving also to restore the electrode into contact at theorigi'- nal 1point when the current is cut oif from the amp;

3. In an arc lamp, an electrode, a second electrode normally inengagement with said first electrode, means for moving saidsecunderstood that the oi-metal element referred to may be constructedof said electrodes from a ond electrode with res ect to said firstelectrode to start an arc etween the two electrodes in the region ofcontact, said means also serving for continuing the movement of saidelectrode to draw the are away from said region of contact on the firstelectrode, and to maintain the. are in a new region whereby the physicalcondition of said conelectrode continues its movement without increasingthe distance between the two electrodes.

,In witness whereof, I have hereunto set tact on the first electrode isprevented from 10 rapid alteration, said means comprising a my hand this30th day of November, 1923. 4

ALOIS IIILN.

ond electrode with resgect to said first electrode to start an arcetween the two electrodes in the region of contact, said means alsoserving for continuing the movement rapid alteration, said meanscomprising a certlflee'te' a ommlan.

Patent No. 1,640,450.

It is hereby numbered patent requiring correction off read on; samepage, line 8t}, Letters Patent should be read with thermostatic element,vthe thermostatic element being so supported that after the secondelectrode has been moved a maximum distance from the first electrode,the second electrode continues its movement without increasing thedistance between the two electrodes.

In witness whereof, I have hereunto set my hand this 30th day ofNovember, 1923.

ALOIS II-ILN.

Granted August so, 1927, to

ALOIS IHLN.

certified that error appears in the printed'specification of the aboveas follows: for the word of these corrections P e 2, line 43, for theword read or; and that the said therein that the same may conform to therecord of the case in the Patent Ofliee.

Signed and sealed this'llth -l day of October,

M. J. MOORE, Acting ammoof Patents.

ommmu of Correction.

Patent No. 1,640,460. Granted August 30, 1927, to ALOIS IHLN.

It is hereby certified that error appears in the printed specificationof the abovenumbered patent requiring eorreetlon as follows: Page 2,line 43, for the word ofi read on; same page, line 86, for the word ofread m; and that the said Letters Patent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Ofi'lee.

Signed and sealed this 11th day of October, A. D. 1927.

[SILL] M. J. MOORE,

Adding Omna'asimwr of Patents.

